Sea-Level Rise and Coastal Hazards

Sea-level rise exposes coastlines to greater risks of flooding and erosion and is expected to affect millions of additional people each year by late this century. Small islands such as the Maldives, Asian mega-deltas such as in Bangladesh, low-lying coastlines in the United States along the Southeast and Gulf of Mexico, and heavily populated coastal cities in Europe such as London and Venice are among the vulnerable locations. Some small island nations could disappear entirely. Portions of some major coastal cities may have to be abandoned.

In addition to the loss of coastal land due to the gradual rise in sea level, there will also be increasing risks associated with wind-driven storm surges, which are responsible for much of the damage and loss of life associated with hurricanes and typhoons. During such events, significant areas of land can be lost instantaneously. As populations are displaced from flooded coastal regions, such as the mega-deltas of Asia and Africa, large numbers of climate refugees could be created, with significant potential for human suffering and security concerns.

Coastal wetlands, including salt marshes and mangroves, are very sensitive to sea-level rise, and large parts of these ecosystems are projected to be lost around the world. The largest losses are likely to be on the Atlantic and Gulf of Mexico coasts of the Americas, the Mediterranean, the Baltic, and small-island regions.